Copper, additive

Copper naphthenate added to the resin at levels between 100—200 ppm effectively extends gel and cure characteristics, resulting in a reduction in exothermic heat (Eig. 7). Copper additives are used widely in commercial laminating resins to modify process exothermic effects. a-Methylstyrene [98-83-9] substituted for styrene at levels of 5—8% has also been used effectively in resins cured at above ambient temperatures. The inhibitor 2,5-di-/-butyIhydroquinone exerts significant exotherm suppression at levels of 200—400 ppm and is useful in high temperature mol ding processes. 

Modifications to Precipitates. Silicon is sometimes added to Al—Cu—Mg alloys to help nucleate S precipitates without the need for cold work prior to the elevated temperature aging treatments. Additions of elements such as tin [7440-31-5] Sn, cadmium [7440-43-9] Cd, and indium [7440-74-6] In, to Al—Cu alloys serve a similar purpose for 9 precipitates. Copper is often added to Al—Mg—Si alloys in the range of about 0.25% to 1.0% Cu to modify the metastable precursor to Mg2Si. The copper additions provide a substantial strength increase. When the copper addition is high, the quaternary Al CuMg Si Q-phase must be considered and dissolved during solution heat treatment. 

Polyunsaturated fatty acids in vegetable oils, particularly finolenic esters in soybean oil, are especially sensitive to oxidation. Even a slight degree of oxidation, commonly referred to as flavor reversion, results in undesirable flavors, eg, beany, grassy, painty, or fishy. Oxidation is controlled by the exclusion of metal contaminants, eg, iron and copper addition of metal inactivators such as citric acid minimum exposure to air, protection from light, and selective hydrogenation to decrease the finolenate content to ca 3% (74). Careful quality control is essential for the production of acceptable edible soybean oil products (75). 

Specia.lty Coppers. Additions are made to copper to satisfy specific needs. Tellurium at a nominal 0.5 wt % addition, sulfur at 0.35 wt %, and lead at 1 wt % enhance machinabiHty. These alloys are identified as C145, C147, and C187, respectively. The solubiHty limit for each element is <0.001%, so that the excess is present as second-phase particles which assist in fracture of chips and lubrication during machining. 

Copper additions seem to be helpful to avoid pitting. Submerged specimens in New York Harbor produced excessive pitting on a 28 percent Chromium stainless but no pitting on a 20 Cr-1 Cu alloy for the period of time tested. 

Copper additions up to about 0.4% give a marked improvement, but further additions make little difference. 

The Krupp work had shown interesting improvements in acid resistance resulting from molybdenum and copper additions, and the use of 2-3% Mo for more difficult acid conditions was soon established. Other early additions were made to overcome susceptibility to intercrystalline corrosion, culminating in the general use, by the early thirties, of titanium additions for carbide stabilisation, followed shortly after by the alternative use of niobium. 

Copper additions appear to have the particular effect of reducing the corrosion stimulating effect of the sulphur content of an iron exposed to acid and the effect is thus less marked in low sulphur irons. Because sulphur can stimulate corrosion in acidic environments, it is usually kept as low as possible in irons to be used under these conditions. A low sulphur content is in any case metallurgically desirable. 

Problem Make the first disconnection to show how these molecules might be made by organo-copper addition to suitable carbonyl compounds. 

Compound (22) was used to synthesise some central nervous system stimulants, the others mostly in i nvestiga Lions of the stereochemistry of the reaction. Vihat generalisation can you make on the stereochemistry of the organo-copper additions ... 

A study of the a-arylation of diazine mono iV-oxides, under Heck-like conditions, also gave emphasis to pyrazines but a number of examples using pyrimidines and pyridazines were also described (Scheme 1). A wide range of aryl chlorides, bromides and iodides was used and the products were easily deoxygenated by catalytic reduction. An interesting feature was the use of a copper additive, which was only required for the pyrimidine reactions, to give a very substantial improvement in yield <06AG(I)7781>. 

Figure 17.16 Cyclooctyne derivatives can be used as alternative click chemistry reactants, as they are capable of reacting with an azide group without the presence of Cu1+ to form a cycloaddition product. This reaction proceeds at a slower rate than the Cu1+-catalyzed process, but it avoids the cytotoxic effects that copper addition can have on cells.

Supplee, W.C. 1964. Observations on the effect of copper additions to purified turkey diets. Poultry Sci. 43 1599-1600. 

Ueno and Hartwig subsequently improved upon this method by developing conditions for allylic alkoxylation that do not require copper additives [97]. In reactions conducted with la generated in sim as catalyst and K3PO4 as base,... 

The photosensitive nature of selenium makes it useful in devices that respond to the intensity of light, such as photocells, light meters for cameras, xerography, and electric eyes. Selenium also has the ability to produce electricity directly from sunlight, making it ideal for use in solar cells. Selenium possesses semiconductor properties that make it useful in the electronics industry, where it is a component in some types of solid-state electronics and rectifiers. It is also used in the production of ruby-red glass and enamels and as an additive to improve the quality of steel and copper. Additionally, it is a catalyst (to speed up chemical reactions) in the manufacture of rubber. 

Acylpyrazines 47 are obtained by Stille reaction of bromopyrazines with 1-ethoxyvinylstannanes, where the coupling is cocatalyzed by copper <2000J(P1)89>. The copper additive increases the yields of products 47 from... 

In the United Stales, (he term copper signifies copper that contains less than 0.5% impurities or alloying elements. Copper-base alloys arc those that contain no less than 40% copper. Additionally, copper appears as a minor, hut important ingredient of several alloys. There are six major types of commercial, unalloyed copper. These are described briefly in Table I. 

The most common and useful additives are copper(I) salts (such as CuCl), which produce high yields of 1 1 adducts in many cases.174 Several examples from the extensive work of the Ciba-Geigy group in Basel are compiled in Scheme 54, with an emphasis on subsequent conversions of the highly functionalized products into important heterocycles.175 These procedures are very simple and have been conducted on a multigram scale. Typically, the halogen component and the acceptor are heated without solvent at 110 °C in the presence of 1-10% CuCl. After several hours, the copper salts are removed by filtration and the product is isolated by distillation. It is clear that the copper additive behaves as more than just an initiator, the additions of electrophilic radicals to electron deficient alkenes like those shown in Scheme 54 would not be likely to succeed otherwise. 

Copper additions to aluminum films enhance electromigration resistance. However, copper does not form volatile chlorides or other halides, and therefore its removal during aluminum plasma etching is difficult. Two methods can be used to promote copper chloride desorption increase the... 

Micellar copper oxide is prepared under conditions such that copper oxide is formed by chemical reaction (CuS04 + NaOH) in the presence of oleic acid as the surfactant and dispersed in hydrocarbon oil (Shpenkov, 1995a Shpenkov and Sagatowski, 1992). Fundamental data with micellar copper additives in motor oil were obtained by Shpenkov from an internal-combustion engine test (Shpenkov, 1995b) using the micellar CuO additive. 

The following procedure was followed for all copper titrations at 25°C and constant pH. The three electrodes were first preconditioned for 30 min in a solution at pH 8 containing 0.1 M Tris base, 0.05 M HCl and sufficient CUSO4 to achieve a pCu of 13.0 to 13.5. The electrodes were then rinsed several times with distilled water and placed for 30 min in a portion of the solution to be titrated. The electrodes were then placed in a fresh 70 mX-portion of the same solution contained in a 100 mJl borosilicate glass beaker and titrated with CUSO4. Sufficient time was allowed for the electrodes to reach steady state potentials after each copper addition. At no copper addition, 60 min was allowed. For copper concentrations 10 M and > 10"7 m, measurements were made 30-60 min and 20-30 min, respectively, after each qopper addition. After reaching steady state, pCu and pH values were... 

There is a little evidence in the literature suggesting that both calculated values of free metal concentration ( 1) and values measured with ISE s ( 8, 9) can be correlated with the biological availability of copper. Additionally, Sunda et (27) have... 

The platinum additive studied was Platinum Plus 3100, supplied by Clean Diesel Technologies, Inc. The copper additive was OS9640K a gift from Lubrizol. The cerium additive was DPX9 from Rhodia, and the iron additive was ferrocene from Aldrich. 

In general, the engine responded well to the different fuel additives. The fuel consumption was hardly affected, although the copper additive resulted in an increase in fuel consumption with 5%. The engine exhaust temperature was also somewhat higher when the copper additive was used (600 K instead of 570 K). Both are thought to be the result of a delayed combustion caused by the copper additive,... 

Tellurium By-product from refining Cu ores Steel and copper additive... 

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